ios - swift 3 : Add text to label if button is pressed

Question

在我的 Xcode 项目中，我有五个空文本标签(即 I、II、III、IV、V)和五个按钮，每个按钮代表一个字母(即 a、b、c、d、e)。

我想用字母填充文本标签 I 到 V，但按字母按钮按下的顺序(即用户按下 c → 标签 < strong>I 包含字母 c；然后用户按下 a → 标签 II 包含字母 a 并且等等)。

你能给我任何提示/解决方案吗？

谢谢，J.

编辑:根据本杰明的建议，我现在做了以下工作:

import UIKit

class ViewController: UIViewController {


    // Letter Buttons
@IBOutlet weak var LetterOneButton: UIButton!
@IBOutlet weak var LetterTwoButton: UIButton!
@IBOutlet weak var LetterThreeButton: UIButton!
@IBOutlet weak var LetterFourButton: UIButton!
@IBOutlet weak var LetterFiveButton: UIButton!

// Word Fields
@IBOutlet weak var WordLetterOne: UILabel!
@IBOutlet weak var WordLetterTwo: UILabel!
@IBOutlet weak var WordLetterThree: UILabel!
@IBOutlet weak var WordLetterFour: UILabel!
@IBOutlet weak var WordLetterFive: UILabel!

// Counter
@IBOutlet weak var CounterLabel: UILabel!

// Skip Button
@IBOutlet weak var SkipButtonLabel: UIButton!

// Define Variables
var index: Int = 0
var labels: [UILabel] = [WordLetterOne, WordLetterTwo, WordLetterThree, WordLetterFour, WordLetterFive]
var letters: [String] = ["A", "B", "C", "D", "E"]



override func viewDidLoad() {
    super.viewDidLoad()

    // Set initial letters for LetterButtons
    LetterOneButton.setTitle("A", for: .normal)
    LetterTwoButton.setTitle("U", for: .normal)
    LetterThreeButton.setTitle("T", for: .normal)
    LetterFourButton.setTitle("O", for: .normal)
    LetterFiveButton.setTitle("S", for: .normal)

    // Add button content to WordField
    // Second Attempt

    //you need to set the tags of each button in order for my method to work
    LetterOneButton.tag = 0
    LetterTwoButton.tag = 1
    LetterThreeButton.tag = 2
    LetterFourButton.tag = 3
    LetterFiveButton.tag = 4

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()



}

// Add button content to WordField
// First Attempt

@IBAction func LetterOneButtonPressed(_ sender: AnyObject) {
    labels[index].text = letters[sender.tag]

    index += 1
}

/**
@IBAction func LetterTwoButtonPressed(_ sender: AnyObject) {
    WordLetterTwo.text = LetterTwoButton.currentTitle
}

@IBAction func LetterThreeButtonPressed(_ sender: AnyObject) {
    WordLetterThree.text = LetterThreeButton.currentTitle
}

@IBAction func LetterFourButtonPressed(_ sender: AnyObject) {
    WordLetterFour.text = LetterFourButton.currentTitle
}

@IBAction func LetterFiveButtonPressed(_ sender: AnyObject) {
    WordLetterFive.text = LetterFiveButton.currentTitle
} **/




// Skip Button Action
@IBAction func SkipButtonAction(_ sender: AnyObject) {
}

}

Answer 1

我的建议是将您的标签和字母放在一个数组中:

var labels: [UILabel] = [label1, label2, ...]
var letters: [String] = ["a", "b", ...]

然后您可以创建一个类变量来跟踪按下了多少个按钮:

var index: Int = 0

然后在所有按钮都链接到“touchUpInside”的 IBAction 中，您可以获取所有这些信息并在每次调用时填充一个标签。这当然需要您将按钮的标签设置为 0、1、2、3、4(分别对应 a 到 e)。

@IBAction func buttonPressed(sender: UIButton){

    switch sender.tag {
    case 0:
        labels[index].text = letters[sender.tag]
    ...
    }

    index += 1

}

编辑:

看到你的代码后，你应该把它改成这样:

 override func viewDidLoad() {
    super.viewDidLoad()

    // Set initial letters for LetterButtons
    LetterOneButton.setTitle("A", for: .normal)
    LetterTwoButton.setTitle("U", for: .normal)
    LetterThreeButton.setTitle("T", for: .normal)
    LetterFourButton.setTitle("O", for: .normal)
    LetterFiveButton.setTitle("S", for: .normal)

    // Add button content to WordField
    // Second Attempt

    //initialize array with real values
    labels = [WordLetterOne, WordLetterTwo, WordLetterThree, WordLetterFour, WordLetterFive]

    //you need to set the tags of each button in order for my method to work
    LetterOneButton.tag = 0
    LetterTwoButton.tag = 1
    LetterThreeButton.tag = 2
    LetterFourButton.tag = 3
    LetterFiveButton.tag = 4

}

对于索引变量和数组，请确保在任何函数之外对其进行初始化。将它们初始化为标签和按钮旁边的类变量，如下所示:

@IBOutlet weak var WordLetterOne: UILabel!
@IBOutlet weak var WordLetterTwo: UILabel!
@IBOutlet weak var WordLetterThree: UILabel!
@IBOutlet weak var WordLetterFour: UILabel!
@IBOutlet weak var WordLetterFive: UILabel!

var index: Int = 0

var labels: [UILabel] = [UILabel]() //empty intialization

var letters: [String] = ["A", "B", "C", "D", "E"]

然后你需要把你的其他方法改成这样:

@IBAction func LetterOneButtonPressed(sender: UIButton) {
    //you can actually omit the switch statement in your case
    labels[index].text = letters[sender.tag]

    index += 1
}

请记住，您需要将每个按钮链接到上述方法。不要为每个按钮设置不同的方法!